Cyazofamid (4-chloro-2-cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfonamide) is an imidazole sulfonamide fungicide introduced by ISHIHARA SANGYO KAISHA, LTD and marketed under the tradename Ranman and having the following chemical structure:

Cyazofamid has a foliar and soil preventative action with some residual activity. Cyazofamid has very low water solubility and a short hydrolytic half-life.
The article “Photodegradation research of cyazofamid” (Journal of agro environment science, 2009, 28 (1):151-155), disclosed degradative dynamics of 10% cyazofamid suspension on the leaves of cucumber plant and in aqueous solution. It was concluded that cyazofamid had faster degradation rate in the aqueous environment. It was also noted that during the day, the degradative half-life of cyazofamid on leaves of cucumber was 63.6 h, while there was no significant degradation in darkness. Thus, it was concluded that natural light was important factor which affected degradation in natural environment. It was found that the photolytic rate of cyazofamid was accelerated with increasing pH value and temperature and increasing light intensity in aqueous solution, in which the light source and light intensity were the main influencing factor. Therefore, it is recommended that the application of cyazofamid should select low temperature and illumination of weak light in the evening so as to play greater efficacy. There have been numerous other attempts in the art to improve the storage stability of cyazofamid but none too successful.
US 20040039039 discloses synergistic combination of imidazole derivatives (cyazofamid) and a dithiocarbamate (Mancozeb). However, this publication fails to disclose a stable composition of cyazofamid.
WO2009123346 discloses a pesticidal aqueous suspension composition (liquid formulation) comprising a sparingly water-soluble pesticide, an organosilicone surface active agent, a viscosity-reducing agent, an antifoaming agent, a pH adjustor and a dispersant.
WO2010021404 (US2011144175A1) discloses a method for controlling degradation of Cyazofamid in solid formulation by using a stabilizer selected from the group consisting of epoxidized animal oil and/or vegetable oil, a nonionic surface active agent of polyoxyethylene, an anionic surface active agent of polyoxyethylene, a polyhydric alcohol and an inorganic basic substance. The preferred basic substance includes an alkali metal hydroxide, an alkali metal carbonate, an alkali metal bicarbonate, an alkaline earth metal hydroxide, an alkaline earth metal carbonate and an alkaline earth metal bicarbonate.
A need remains in the art for stable formulations of cyazofamid having improved storage stability. The present invention adequately addresses these and other needs existing in the art.
Thus, there is an unfulfilled need in the art for a storage stable formulation comprising cyazofamid with enhanced storage stability and reduced degradation.